This paper explores the challenges faced by policy makers and activists as they grapple with how to represent and respond to the complex environmental process that is climate change. Taking Bruno Latour’s Politics of Nature and Facing Gaia as a provocation, this paper draws on ethnographic research conducted with those working to reduce the carbon emissions of the city of Manchester in the UK to provide empirical depth to some of the radical claims that have been made as to the way in which climate change and other anthropogenic processes are dismantling a modernist divide between nature and society. I consider how and why climate change appears to unsettle certain categories of truth, representation, responsibility and action. In doing so I demonstrate how the political struggle over environmental futures does not just entail questions about how we should act, but also poses fundamental questions about how we should think. I consider the implications of these questions not only for the transformative project of urban planning but also for the descriptive practices of anthropology.